Over the past twenty to thirty years, a large number of attempts have been made to construct a bowling pin either partially or wholly of resinous plastic materials in an attempt to provide a pin which is either more durable or less expensive than wooden pins, while at the same time retain the properties of wooden pins. In this regard, numerous patents disclose attempts to construct bowling pins of plastic, and some examples of such patents are the following: U.S. Pat. Nos. 4,351,786, 4,210,992, 4,165,875, 4,123,057, 4,012,386, 3,984,104, 3,971,837, 3,580,577, 3,572,710, 3,478,134, 3,346,258, 3,329,430, 3,301,560, 3,268,636, 3,231,274, 3,229,978, 3,251,598 and 3,169,766.
These numerous prior attempts to construct a bowling pin of resinous material, as by molding the pin or parts thereof of plastic, have been unsuccessful for numerous reasons. For example, many of the prior attempts have involved constructing the bowling pin of numerous individual plastic parts which are then assembled together, such being exemplified by aforementioned U.S. Pat. Nos. 3,251,598 and 4,351,530. Other attempts have involved the fabricating of the pin by constructing it of numerous different materials, such as by molding the core or some part of the pin of one material (such as a foamed plastic), and thereafter molding some or all of the remaining structure of the pin of a different material, such construction being exemplified by aforementioned U.S. Pat. Nos. 3,971,837 and 3,229,978. Still other attempts have involved using plastic in combination with wood or metal, such being illustrated by aforementioned U.S. Pat. Nos. 3,971,837 and 4,210,992. Construction techniques of the aforementioned types, however, are generally complex and expensive. Further, the multiple-part construction is generally expensive and effects pin durability.
Of most significance, however, with respect to the numerous prior attempts to construct bowling pins either wholly or partially of a plastic material is the inability of the plastic pin to possess the properties necessary to functionally react in a manner equivalent to a wooden pin. In this regard, the properties and characteristics of bowling pins are accurately determined and defined, which properties and characteristics have been defined in terms of wooden pins in view of their long and accepted usage. Hence, since a bowling pin has a very precise and well defined geometry, and also has very precisely defined properties such as weight, radius of gyration, center of gravity and the like, this being necessary in order for the pin to have the desired "action" when used in the sport of bowling, most prior plastic pins have hence been unable to conform to or meet the very rigid properties and characteristics defined for bowling pins and at the same time still possess the desired durability.
Accordingly, the present invention relates to an improved bowling pin constructed entirely of a plastic material, the pin being formed primarily by a one-piece integrally molded hollow plastic body which defines the entirety of the pin except for a small plastic plug which is seated in the bottom base surface of the pin for closing off the hollow interior of the body. This improved plastic pin has a hollow interior defined by a bore which extends concentrically throughout the longitudinal extent of the pin from the bottom plug to a point just short of the upper extremity of the pin. The hollow body is of predetermined contour throughout its length so that the pin possesses the required properties and characteristics so as to permit it to perform in a manner similar to a wooden pin. This plastic pin is also believed to provide significantly improved durability in comparison to a conventional wooden pin.
It has already been attempted to construct a bowling pin using a one-piece integrated molded plastic body as the primary pin structure, with this plastic primary body having a bore extending longitudinally upwardly therethrough, as illustrated by U.S. Pat. No. 4,012,386. However, this latter pin is not capable of possessing or conforming to the required properties and characteristics of the pin in accordance with defined standards, particularly since this latter pin due to its cross-section throughout its longitudinal extent will not possess a proper radius of gyration so as to permit it to react in the same manner as a wooden pin.
In contrast, the improved pin as defined in this application is believed to overcome the aforementioned disadvantages, including the disadvantages possessed by the pin of aforementioned U.S. Pat. No. 4,012,386.
Other objects and purposes of the invention will be apparent to persons familiar with structures of this type upon reading the following specification and inspecting the accompanying drawing.